Conversions

3 minutes = 0.05 hours

6 minutes = 0.1 hours

1 hour and 15 minutes (1:15) = 1.25 hours

Calculating Time

Time = Distance / Groundspeed

Example:

Distance = 30 NM

Groundspeed = 100 knots

Time = 30 / 100 = .3 hours

(.1 hour = 6 minutes)

.3 x 6 = 18 minutes

Rule of Thumb

Change the fraction that represents groundspeed (Groundspeed / 60) to an equivalent fraction by dividing the numerator and denominator by 2. The new numerator represents the distance flown and the new denominator represents the time in minutes.

Example:

Groundspeed = 120 knots

120/60 = 60/30 = 30/15 = 15/7.5

The aircraft will travel 120 NM in 60 minutes, 60 NM in 30 minutes, 30 NM in 15 minutes, and 15 NM in 7.5 minutes